Electrical conductor.



C. A. KELLER.

ELECTRICAL CONDUCTOR.

APPLICATION FILED JULY13,1908.

Patented June 14,1910.

2 SHEETS-SHEET 1.

Illlllrlllllllllllllllllll C. A. KELLER.

ELECTRICAL CONDUCTOR.

APPLIOATION FILED JULY 13,1908.

F49'. L. 2 SHEETS-SHEET z.

2 f i L l; I@ i e il y l/ @11i @Eff/0725? UNITED sTATEs PATENT oEEIcE.

CHARLES ALBERT KELLER, OF PARIS, lFRANCE.

ELECTRICAL CONDUCTOR.

To all 'whom 'it may concern:

Be it known that I, CHARLES ALBERT KELLER, a citizen of the Republic of France, residing at Paris, in France, have invented new and useful Improvements in or Relating to Electrical Conductors, of which the following is a specification.y

This invention relates to electrical conductors, more particularly those used in conjunction with the electrodes of electric furnaces and-the like and has for its object to improve the conductor and the manner in which it is connected to its electrode.

The connections at present used for the electrodes of electric furnaces, whatever be the type, have the drawback of necessitating the loss of a certain length of the electrode by reason of the tightening or adjusting devices for the conductors supplying electric current to the carbon. Numerous devices have been designed for avoiding this drawback, and certain connections have been produced in which contact is effected by pressure on one end of the electrode. These devices still have, however, certain drawbacks which are entirely obviated by the construction forming the subject of the present invention. v

According to this invention, a recess which is preferably undercut, is formed in the head of the carbon electrode into which one end of the conductor is placed, the end of the conductor being of smaller cross-section than the recess, the shape of which it preferably resembles. Metal in a molten condition is then poured into the recess the conductor being thus physically lconnected in a permanent manner toits electrode and a thorough electrical connection being established.

The metallic conductor comprises a cast iron or steel sheath inclosing a hollow copper core through which cooling water circulates. Recesses are formed 1nv that portion of thel conductor which lies within the carbon electrode, which recesses the molten metal enters and partly ills an improved contact bein thus obtained and air gaps being rovi ed which tend to prevent the formatlon of induced currents.

In the accompanying drawings: Figure l Specication of Letters Patent. Patented J une 14, 1910, Application filed July 13, 1908.

Serial N0. 443,267.

is a vertical section of an electrode provided with one form of connection according to this invention. Fig. 2 is a vertical section on line 2 2 of Fig. 1. Fig. 3 is a horizontal cross-section on line 3 3 of Fig. 2. Fig. 4 is a vertical section of one form of connection applied to two electrodes, and Fig. 5 is a horizontal section on line 5 5 of Fig. 4.

In the head of the carbon electrode a (Figs. l-S) a recess Z) is formed into which is introduced the electric conductor c which supplies the current. The recess b is preferably widened toward its base "forming a truncated pyramid or a truncated cone. The metallic conductor c is preferably of the same outer shape as the recess b but of smaller cross-section, so that a space d is left between its sides and the walls of the recess within which it is properly centered. The whole device is heated, and the space d, separating the conductorv c .from the carbon of the electrode a, is filled with a metal, in a molten state which is a good conductor of electricity, copper being preferably employed. In this way a thorough contact is established between the metallic conductor c and the carbon electrode a. The connection thus obtained is as intimate possible, and at the same time is extremely simple since all adjusting or tightening devices are `done away with.

To lengthen the life of the electrode, the interior of the metal conductor o is continually cooled by a current ofA Water circulating in suitably provided conduits the precise construction of which may vary to suit requirements. A convenient manner 1s however, shown in the drawings the conductor comprising a hollow cast iron or steel sheath e which is molded around the copper part f inclosing a tube g for the circulation of the cooling water. The copper parts f extend outside the sheath e to form terminals h to which the electric conductors are applied. The portion of the sheath c which lies within the recess in the electrode a is provided with openings z' into which the molten copper penetrates thus forming part of the outer surface or sheath o. In thls way, the current supplied to the copper terminals is `transmitted direct in the longitudinal direction by the copper conductors f and then transmitted, mostly by direct Contact, to the carbon of the electrode a.

The tubes g constituting the cooling conduits are arranged near the outer wall of the conductor this being the hottest portion thereof and the copper conductor is recessed or hollowed as shown in the drawing, in order to reduce the wei ht of the copper used. ln that way a tu ular conductor is obtained, eminently suitable for the circulation of alternating currents. Finally the openings z' already referred to constitute air gaps for the magnetic field generated by the lower conductor. The said openings and a groove Z made throughout the length of the cast iron part, prevent the formation of induced currents whchwould bring about a supplementary shifting of phase of the current and lower the power factor of the cir cuit.

This invention is applicable to the connections of single electrodes in which case a single conductor is provided, or to several electrodes, when one conductor to each electrode is preferably provided. In the latter case, and when there are for instance two electrodes the two conductors c and c (Figs. 4 and 5) are connected by suitable ribs which keep them parallel, and water circulates from one conductor to the other and the connection of the two electrodes thus comprises a single device.

This invention does away with all tightening or adjusting devices for the connection -and all deterioration due to defective tightening and to the proximity of the connection pieces to the electric furnace when the electrode is short. Further, it is possible to utilize a much greater length of each electrode owing to the contact being arranged in the manner described and the conductor cooled as above set forth.

With a contact made in accordance with this invention when electrodes say of 1.6 meters are employed, the coeiicient of absolute utilization of the electrodes reaches as much as 85%. Each time that a worn out electrode is removed, the copper whereby the contact was originally effected is taken out, and after being melted, can again be used for the same purpose.

This invention 1s applicable to the electrodes of all electric furnaces, even those which are surmounted by a reverberatory arch, under which the new conductor can be introduced, the construction of the electrode and conductor being such that its full length can be employed, no injurious free spaces being thus left as has hitherto been the case.

It will thus be seen that the connection described is of a thorou hly reliable nature and at the same time effects great economy in the wear of the electrodes.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, l declare that what l claim is l. An electrical connection comprising in combination, an electrode provided with an opening, an electrical conductor provided with a hollow portion adapted for insertion into said opening and having an aperture extending from said hollow portion outwardly lto the sides of said conductor and abreast of the wall of said opening, and a conducting fusible element disposed in said aperture and extending therethrough into l engagement with the wall of said opening for uniting said conductor and electrode.

2. An electrical connection comprising in combination an electrode provided with a truncated cone shaped opening, an electrical conductor inserted into said opening, said conductor being provided with a plurality of recesses in the inserted portion, and a fusible electrically conducting element filling said recesses and the interspace between said conductor and the walls of said opening.

3. An electrical connection comprising in combination, an electrode provided with an opening, a conductor provided with a longitudinally disposed hollow portion and having one end inserted in said opening, said conductor having apertures in its side walls lying abreast of the wall of said opening, and a fusible element of electrically conducting material disposed in said opening and extending into said apertures for uniting the electrode with said conductor.

Ll. An electrical connection comprising in combination, an electrode provided with a rectangular truncated cone shaped opening, a conductor provided with a sheet of conducting material having a portion complementally formed withv respect to the formation of said opening and reduced in size with respect thereto, said sheet having lateral openings, and a fusible connection of conducting material uniting said electrode and conductor.

5. An electrical connection comprising in combination, an electrode provided with an opening, a hollow conductor adapted for insertion in said opening and having apertures extending from its hollow interior portion to its exterior and opening abreast of the wall of said opening, means for affording passage of a cooling agent in said conductor, and a fusible element of electrical conducting material disposed in said interior about said means and extending through said apertures into engagement with the wall of said opening for uniting said electrodes with said conductors.

6. An electrical connection com rising in combination an electrode provide with an opening, an electrical conducting member inserted into Suid opening, un iron sleeve 1nclosing Suid conducting member and extending into said opening said sleeve being provided with a plurality of a ertures Within said opening, said member being provided with a longitudinal groove, and a fusible conductive element connecting said sleeve 10 and conducting member With the walls of the opening.

ln testimony whereof l :iilix my signature in presence of two witnesses.

CHARLES ALBERT KELLER. Witnesses N. DUM, RENIER. 

